Electronic tracking and ranging system

ABSTRACT

An electronic tracked and ranging system is disclosed. Electronic tracking and ranging system applies interferometer principles to determine ranging distance from a monitor unit  10  to a tracked unit  12 . In particular, the system transmits a monitor direct sequence spread spectrum (MDSSS)  52  signal from a monitor unit  10  to a tracked unit  12 . Afterwards, tracked unit  12  transmits a tracked direct sequence spread spectrum (TDSSS)  56  signal. Finally, monitor unit  10  receives TDSSS  56 , performs a comparison to a reference MDSSS signal  52  locks between MDSSS signal  52  and TDSSS signal  56  and outputs distance between monitor unit  10  and tracked unit  12  using several phase comparisons. Multiple frequencies within MDSSS signal  52  are phase detected so as to increase accuracy of monitor unit  10  ranging distance to tracked unit  12.

TECHNICAL FIELD

This invention relates to an electronic tracking and ranging system.More specifically, an electronic tracking and ranging system thatutilizes phase differences between a monitor signal and a signalreceived from a tracked unit, where multiple frequency components ofboth monitor unit and tracked unit signals are phase detected todetermine the ranging distance of an object including a tracked unitfrom a monitor unit.

BACKGROUND ART

There is a need for an improved electronic tracking and ranging systemto account for RF signal variations due to RF signal attenuation fromenergy waves, such as electromagnetic energy, are being reflected offand being dissipated in surrounding areas. Present electronic trackingand ranging systems require a special calibration procedure or specialsettings so that a user can determine range or track an object within agiven area or a given location. In addition, other problems with presentelectronic tracking and ranging systems for objects include the use ofvery fine timing intervals for accurate measurements, i.e., within acouple of nano-seconds, and inherent delays in a transponder responsetime and transponder variations with temperature changes may causelarger ranging variations than the time interval being measured. Thus,there is a need for an improved electronic tracking and ranging systemthat provides a improved solution to the above problems such asincreasing accuracy of locating an object including a tracked unit, evenwhen the transmitted signal is attenuated as well as provide otheradvantages over present tracking and ranging systems.

DISCLOSURE OF THE INVENTION

Disclosed is an electronic ranging and tracking systems for objects thatapplies interferometer principles to determine distance between amonitor unit to a tracked unit. In particular, the monitor unittransmits a monitor direct sequence spread spectrum (MDSSS) signal to atracked unit. Afterwards, tracked unit receives MDSSS signal andtransmits back to monitor unit a tracked direct sequence spread spectrum(TDSSS) signal. Finally, the monitor unit receives TDSSS signal,performs a comparison to MDSSS signal, locks signals between MDSSS andTDSSS, and outputs at least one phase difference between MDSSS signaland TDSSS signal. During the locking process, TDSSS signal comprisingthree frequencies, i.e., a carrier frequency, a chipping frequency ofpseudo-random noise (PN) sequence, and a repetition frequency ofpseudo-random noise (PN) sequence, which are utilized within the monitorunit to calculate ranging distance between the tracked unit and themonitor unit.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is the block diagram for an interferometer electronic trackingsystem of the present invention.

FIG. 2 is a schematic of a monitor unit for the present invention.

FIG. 3 is a schematic of a tracked unit for the present invention

FIG. 4 illustrates a first phase comparison of a monitor unit of thepresent invention.

FIG. 5 illustrates a second phase comparison of a monitor unit of thepresent invention.

FIG. 6 illustrates a third phase comparison of a monitor unit of thepresent invention.

FIG. 7 illustrates a front view of a housing for a tracked unit for thepresent invention

FIG. 8 illustrates a front view and a back view of a housing for amonitor unit for the present invention.

FIG. 9 displays operating field of activity of the system.

MODES FOR CARRYING OUT THE INVENTION

FIG. 1 is the block diagram for an interferometer electronic trackingsystem 8. Interferometer electronic tracking system 8 comprises amonitor unit 10 and a tracked unit 12. Monitor unit 10 comprises amonitor programmable logic array 14, a monitor reference oscillator 16,a monitor micro-controller 18, a first monitor modulator 20, a secondmonitor modulator 21, a monitor phase detector 22, a monitor poweramplifier 24, a monitor duplexer 26, a monitor low noise amplifier (LNA)28, an antenna switch 30, a first monitor antenna 32, and a secondmonitor antenna 34. Tracked unit 12 comprises a tracked programmablelogic array 36, a tracked reference oscillator 38, a trackedmicro-controller 39, a tracked modulator 40, a tracked phase detector42, a tracked power amplifier 44, a tracked duplexer 46, a tracked lownoise amplifier (LNA) 48, and a tracked antenna 50. Monitor unit 10transmits a monitor direct sequence spread spectrum (MDSSS) signal 52 totracked unit 12 including a monitor reference frequency 70 (see FIG. 6)and a monitor pseudo-random noise (PN) sequence 65 (see FIG. 5). MDSSSsignal 52 waveform is a waveform like that used by a Wireless Local AreaNetwork (WLAN) utilizing direct sequence spread spectrum (DSSS)technology. Tracked unit 12 receives MDSSS signal 52 and transmits tomonitor unit 10 a tracked direct sequence spread spectrum (TDSSS) signal56 including a tracked reference frequency 72 (See FIG. 6) and a trackedpseudo-random noise sequence 61 (See FIG. 5). TDSSS 56 waveform is awaveform like that used by a Wireless Local Area Network (WLAN)utilizing direct sequence spread spectrum (DSSS) technology. Following,monitor unit 10 receives TDSSS signal 56 and calculates ranging distancebetween monitor unit 10 and tracked unit 12 using multiple frequencyphase comparisons between MDSSS signal 52 and TDSSS signal 56.

FIG. 2 is a schematic of a monitor unit 10 for an interferometerelectronic tracking system. Monitor unit 10 generates a monitorreference frequency 70 from a monitor reference oscillator 16 such as avoltage-controlled oscillator or the like. Monitor programmable logicarray 14 has a phased-lock loop which locks monitor reference oscillator16 to a multiple of a clock frequency of the monitor programmable logicarray 14. The clock frequency is derived from a crystal oscillator 11.In this embodiment, monitor reference frequency 70 is a carrierfrequency such as a Radio Frequency (RF). Furthermore in thisembodiment, carrier frequency is 915 MHz. Monitor reference oscillator16 output electrically connects to an input port of a first monitormodulator 20. First monitor modulator 20 functions to modulate carrierfrequency with a monitor pseudo-random noise (PN) sequence 65 togenerate a monitor direct sequence spread spectrum (MDSSS) signal 52that will be sent through monitor power amplifier 24.

In this embodiment, monitor PN sequence 65 is applied at the rate termedthe chipping frequency. Monitor PN sequence 65 modulates carrierfrequency to create signal spreading of carrier frequency. Inparticular, chipping frequency is the rate at which monitor PN sequencespreads the bandwidth of carrier frequency. Also, chipping frequencydetermines desired monitor frequency bandwidth, where monitor frequencybandwidth is twice the chipping rate. In this embodiment, a 915 MHzcarrier frequency with a chipping frequency of 12 MHz generates amonitor frequency bandwidth extending over a frequency range of 903 MHzto 927 MHz. Furthermore, monitor PN sequence 65 has a finite length,which finite length is divided into chipping frequency to yield arepetition rate 57 wherein monitor PN sequence 65 repeats. The length ofmonitor PN sequence 65 determines this repetition rate 57 becauserepetition rate 57 is the chipping rate divided by length of monitor PNsequence 65. In this embodiment, a monitor PN sequence 65 with a lengthof 40 characters results in a repetition rate 57 of 250 kHz.Alternatively, a monitor PN sequence 65 with a length of 133 charactersresults in a repetition rate of 75.2 kHz.

Within monitor programmable logic array 14, monitor PN sequence iscreated by a spreading sequence originating from a set of “source”registers (not shown in Figure) within monitor programmable logic array14. Monitor PN sequence 65 loads into a first shift register 13 and asecond shift register 15 within monitor programmable logic array 14,whereby monitor PN sequence is shifted at the chipping rate. Inparticular, monitor programmable logic array 14 including first shiftregister 13 with a digital tap line (not shown in Figure) controlled bymonitor micro-controller 18 to spread monitor PN sequence at chippingfrequency, outputting a single bit value at the chipping rate of shiftedmonitor PN sequence to first monitor modulator 20. Additionally, monitorprogrammable logic array 14 includes second shift register 15 with adigital tap line (not shown in Figure) controlled by monitormicro-controller 18 to spread monitor PN sequence 65 at chippingfrequency, outputting a single bit value at the chipping rate of shiftedversion of monitor PN sequence 65 to second monitor modulator 21. Eachtime first shift register 13 or second shift register 15 has shiftedmonitor PN sequence 65 a number of times equal to the length of monitorPN sequence 65, first shift register 13 or second shift register 15 arere-loaded from the respective “source” registers (not shown in Figure).

Following, monitor direct sequence spread spectrum signal (MDSSS) 52,i.e., monitor signal, is electrically connected to a monitor poweramplifier 24 to boost monitor signal strength. Monitor power amplifier24 sends monitor signal 52 through monitor duplexer 26, such as aMini-circuits RCM-12-4-75 or a functional equivalent, directing monitorsignal 52 to first monitor antenna 32, such as a circuit board patchantenna, for transmission to tracked unit 12. Preferably, monitorreference oscillator 16, monitor modulator 20, and monitor poweramplifier 24 functional blocks would be contained in one electroniccircuit such as a Phillips SA900 or a functional equivalent.

FIG. 3 is a schematic of a tracked unit. Tracked unit 12 is atransponder. A tracked antenna 50 on tracked unit 12 receives monitorsignal 52. Preferably, tracked antenna 50 is a circuit board patchantenna. Tracked duplexer 46, such as Mini-circuits RCM 12-4-75 oralternatively a functional equivalent, electrically connects MDSSS 52 toa tracked low noise amplifier (LNA) 48, such as Agilent ABA-51563 or afunctional equivalent, for signal amplification. Afterwards, monitor PNsequence transmitted within monitor signal 52 is mixed with tracked PNreference sequence within a tracked phase detector, in which in thisembodiment is a tracked mixer 42, such as Minicircuits ADE-2 or afunctional equivalent. Tracked mixer 42 generates a tracked PN errorsequence 77, which tracked PN error sequence 77 is transmitted to atracked micro-controller 39, such as Microchip PIC16F873, Altera NEOSinside EP1C3, or a functional equivalent circuit, which controls atracked programmable logic array 36, such as Altera EP1C3 or afunctionally equilvalent circuit.

Tracked programmable logic array 36 shifts tracked PN sequence 61 andoutputs a shifted version of tracked PN sequence 61 to a trackedmodulator 40. Tracked modulator 40 outputs modulated tracked PN sequence61, which shifted version of tracked PN sequence 61 is input to trackedmixer 42, wherein tracked PN error sequence 77 is again regenerated.Afterwards, the above steps are repeated until tracked PN sequence 61locks with monitor PN sequence 65. As such, the above steps ofregenerating monitor PN sequence within tracked unit 12 to adjust forphase errors generated within tracked unit 12, avoids phase inaccuraciesintroduced by conventional transponders that don't regenerate monitor PNsequence 65. After locking between tracked PN sequence 61 and monitor PNsequence 65 occurs, tracked modulator 40 outputs a tracked directsequence spread spectrum signal (TDSSS), i.e., tracked signal 56,outputting tracked signal 56 though tracked amplifier 44. Trackedamplifier 44 electrically connects to tracked antenna 50 through trackedduplexer 46 for transmitting TDSSS signal 56 to monitor unit 10.

TDSSS signal 56 embodies three frequencies, i.e., a carrier frequency 72(FIG. 6), a chipping frequency 61 (FIG. 5), and a repetition rate 55(FIG. 4) (i.e., the rate of repetition of monitor PN sequence). Thesethree frequencies have an associated wavelength for one complete cycle.Using monitor phase detector 22 measurements, a user compares phase oftracked signal 56 to monitor signal 52 for various frequency components.These phase differences between tracked signal 56 to monitor signal 52is used to determine ranging distance between monitor unit 10 andtracking unit 12. The ranging distance results from that portion of thewavelength that corresponds to a proportion of a phase difference ascompared with a full cycle, i.e., 360 degrees. Coarse distancecalculation is done with the largest wavelength frequency. Afterwards,coarse distance calculation is used in conjunction with a smallerwavelength frequency component to determine with increased accuracy theranging distance for the portion of the distance that is in excess of aninteger number of wavelengths. Prior art would have counted within adigital counter the number of frequency intervals that are repeatedwhile this present invention would compare phase shift between differentfrequencies of DSSS signal 56 and MSSS signal 52, and use these phasedifferences of each frequency component for measuring ranging distancebetween tracked unit 12 and monitor unit 10.

Referring to FIG. 2, a first monitor antenna 32 and a second monitorantenna 34 receives tracked signal 56. In this embodiment, first monitorantenna 32 and second monitor antenna 34 are cross-polarized. Antennaswitch 30 selects first monitor antenna 32. Tracked signal 56 receivedby first monitor antenna 32 electrically connects to monitor duplexer26, which directs tracked signal 56 to monitor low noise amplifier 28for boosting signal level. Afterwards, tracked signal 56 is frequencymixed with monitor signal 52 to generate a monitor PN error signal 83.Monitor PN error signal 83 is electrically connected to monitormicro-controller 18. Monitor micro-controller 18 generates a monitor PNshift control 85 which is electrically connected to monitor programmablelogic array 14. Monitor programmable logic array 14 shifts monitor PNsequence 65 and applies a shifted version of monitor PN sequence 65(FIG. 5) to second modulator 21 that connects to monitor mixer 22. Inthis embodiment, monitor PN sequence 65 has a repetition rate 57, i.e.,monitor first frequency component, of 250 kHz.

FIG. 4 illustrates first phase comparison technique of monitor unit 10interferometer of present invention. In particular, detection of TDSSS56 involves shifting monitor repetition rate 57 until it locks withtracked first frequency component 55 of TDSSS signal 56. As explainedabove in paragraph [0016] monitor programmable logic array 14 implementsa first shift register 13 (shown in FIG. 2) and a second shift register15 (Shown in FIG. 2) and a digitally controlled tap (not shown inFigure) along each shift register to calculate a first phase difference59 between tracked first frequency component 55 relative to monitorrepetition rate 57, i.e., monitor first frequency component. Afterwards,first phase comparison is repeated until tracked first frequencycomponent 55 locks with monitor repetition rate 57. In this embodiment,within monitor programmable logic array 14, a phase comparison is madebetween a tracked first frequency component 55, i.e., a 250 KHz and amonitor repetition rate 57 of 250 KHz using a first shift register 13and second shift register 15, as shown in FIG. 2, to calculate firstphase difference 59.

First phase difference 59 determines a coarse measure of rangingdistance between tracked unit 12 and monitor unit 10. In thisembodiment, a first frequency comprising a 250 kHz reference frequencyhas roughly a wavelength in free space of 4,000 feet. As such, firstphase difference 59 is appropriate for creating a ranging distance errorbetween monitor unit 10 and tracked unit 12 of less than 4,000 feet. Inpractice, monitor mixer 22 generates a PN phase error, typically around5 degrees, which gives a first phase difference measurement rangingdistance error of over 55 feet. Thus, we still need more accuracy ofranging distance between tracked unit 12 and monitor unit 10.

FIG. 5 illustrates a second phase comparison of a monitor unit 10 of thepresent invention. As such, to achieve more accuracy, we need to a use asecond tracked frequency 61 of TDSSS signal 56 having a mediumwavelength. As such monitor programmable logic array 14, a second phasecomparison is made between a monitor PN sequence 65 (a second monitorfrequency component) having a chipping frequency of 12 MHz compared toTDSSS 56 including a second tracked frequency component 61, which is inthis embodiment a 12 MHz signal, to generate a second phase difference63. Second phase difference 63 is used in conjunction with first phasedifference 59 to increase accuracy of determining distance betweentracked unit 12 and monitor unit 10. For example, second trackedfrequency component 61, which second tracked frequency component 61 hasa wavelength of about 69 feet, which determines the number of cycles of69 feet involved in determining ranging distance of tracked unit 12.Prior art would have counted pulses by determining the number ofconstructive and destructive phase differences between a referencesignal and received signal while the present invention uses more thanone phase detection. More specifically, this invention uses more thanone phase detection to measure with increasing accuracy, i.e., withincreasingly more accurate discrete steps, to generate ranging distancebetween tracked unit 12 and monitor unit 10.

FIG. 6 illustrates a third phase comparison of a monitor unit 10 of thepresent invention. To achieve even more accuracy, this step involvesusing a third tracked frequency component 72, i.e. 900 MHz band, of theTDSSS signal 56, where monitor programmable logic array 14 performs athird phase comparison between monitor reference frequency 70, i.e.,monitor third frequency component, which in this embodiment is carrierfrequency, and a tracked third frequency component 72, outputting athird phase difference 74, wherein carrier frequency has a wavelength onthe order of 1 foot. This third phase comparison provides very fine stepresolution in conjunction with coarse phase error 59 to increasecalculation accuracy of tracked unit ranging distance from monitor unit.

Referring to FIG. 2, a measurement of a received signal strengthindication (RSSI) from first monitor antenna 32 is made based onamplitude difference between monitor signal 52 and TDSSS signal 56.Following, antenna switch 30 connects second monitor antenna 34,measures shift level, and calculates amplitude difference betweenmonitor signal 52 and TDSSS signal 56. A difference is calculatedbetween first monitor antenna 32 and second monitor antenna 34 receivedpower levels to determine if tracked unit 12 getting closer to monitorunit 10. From this difference in first monitor antenna 32 measured powerand second monitor antenna 34 measured power, a relative angle oftracked unit 12 is determined in relation to monitor unit 10. As such,the ratio of power from first monitor antenna 32 to second monitorantenna 34, minus first monitor antenna loss and second monitor antennaloss, equates to the cotangent of an angle 51 relative to axis of firstmonitor antenna 32.

FIG. 7 illustrates a front view of a housing for a tracked unit for thepresent invention. A tracked unit 12 (not shown) is disposed on anintegrated circuit that is placed within tracked unit housing 94 wherefirst strap 90 and second strap 92 are attached to a person to betracked, such as a child. Further, first button 96 activates ordeactivates the tracked unit (not shown). In this embodiment, thetracked unit housing 94 includes a working watch where second botton 98sets the watch time and third button 102.

FIG. 8 illustrates a front view and a back view of a housing for amonitor unit for the present invention. A monitor unit 10 (not shown inFigure) is disposed on an integrated circuit (not shown in Figure)placed within monitor unit housing 101, where monitor micro-controller18 is electrically connected to a monitor compass 104, such as a LiquidCrystal Display (LCD), which monitor compass hand 105 displays locationof a tracked unit 12 (not shown in Figure). A user may adjust a firstrange adjustment dial 107 and a second range adjustment dial 108,allowing a user to select a zone, whereby monitor unit 10 tracks atracked unit 12 (not shown in Figure).

FIG. 9 displays operating field of activity of the system. In thisembodiment, there are four zones of coverage. Each zone shows a user arelative distance between a monitor unit and a tracked unit. A firstzone 115, i.e., safe zone, means a tracked unit 10 is within close rangeof a monitor unit 10. In this Figure, object 122 including a trackedunit 12 (not shown) is within safe zone 115 and first light 110 (shownin FIG. 8) is lit displaying that object 122 is within safe zone 115. Inthe alternative, if an object including a tracked unit (not shown inFigure) was within a second zone 117, which is a first ring of coverageaway from safe zone 115, a second light 112 (shown in FIG. 8) would belit. In yet another alternative, if an object including a tracked unit12 (not shown in Figure) is within a third zone 120, a third light 118(shown in FIG. 8) would be lit. In yet a further alternative, fourthzone 125 is the area outside of third zone of coverage 120. As such,each ring of coverage, i.e., second zone 117 and third zone 120 areconcentric rings of coverage to alert a user of a relative change inranging distance of said monitor unit 10 (FIG. 1) to said tracked unit12 (FIG. 1).

Information herein shown and described in detail is fully capable ofattaining the above-described object of the invention and the presentembodiment of the invention, and is, thus, representative of the subjectmatter which is broadly contemplated by the present invention. The scopeof the present invention fully encompasses other embodiments which maybecome obvious to those skilled in the art, and is to be limited,accordingly, by nothing other than the appended claims, whereinreference to an element in the singular is not intended to mean “one andonly one” unless explicitly so stated, but rather “one or more.” Allstructural and functional equivalents to the elements of theabove-described embodiment and additional embodiments that are known tothose of ordinary skill in the art are hereby expressly incorporated byreference and are intended to be encompassed by the present claims.

Moreover, no requirement exists for a device or method to address eachand every problem sought to be resolved by the present invention, forsuch to be encompassed by the present claims. Furthermore, no element,component, or method step in the present disclosure is intended to bededicated to the public regardless of whether the element, component, ormethod step is explicitly recited in the claims. However, one skilled inthe art should recognize that various changes and modifications in formand material details may be made without departing from the spirit andscope of the inventiveness as set forth in the appended claims. No claimherein is to be construed under the provisions of 35 U.S.C. § 112, sixthparagraph, unless the element is expressly recited using the phrase“means for.”

INDUSTRIAL APPLICABILITY

This invention applies industrially to an electronic tracking andranging system. More specifically, the present invention appliesindustrially to an object tracking and ranging system that utilizesphase differences between monitor reference signal and monitor receivedsignal from multiple frequency bands to increase accuracy of locatingobjects. The present invention reduces positioning inaccuracy due tosurrounding area.

1. An electronic system for locating an object comprising: a monitoring unit; a tracked unit placed on said object receiving a monitor direct sequence spread spectrum (MDSSS) signal from said monitoring unit and transmits a tracked direct sequence spread spectrum (TDSSS) signal to said monitoring unit; and a first phase detector placed on said monitor unit to compare a first frequency component of said tracked direct sequence spread spectrum signal to a monitor first frequency component creating a first phase difference utilized for a coarse accuracy determination of a object ranging distance relative to said monitor unit.
 2. An electronic system as recited in claim 1, further comprising: a second phase detector included within said monitor unit that compares a tracking second frequency component of said TDSSS signal with a monitor second frequency component to create a second phase difference; and a first detector phase error output determines number of repeated frequency periods of said second frequency component of said TDSSS signal for a medium accuracy determination of said object ranging distance relative to said monitor unit.
 3. An electronic system as recited in claim 2, further comprising: a third phase detector comparing a third frequency of said TDSSS signal with a monitor third frequency component to create a third phase difference; and an output of second phase detector determines number of repeated frequency cycles of said tracked third frequency of said TDSSS signal for fine accuracy determination of said object ranging distance relative to said monitor unit.
 4. An electronic system as recited in claim 1, wherein said first frequency of said TDSSS is a repetition rate of said tracked pseudo-random noise sequence and said first monitor frequency component is a repetition rate of said monitor pseudo-random noise sequence.
 5. An electronic system as recited in claim 1, wherein said second frequency component of said TDSSS signal is a chipping frequency of said tracked pseudo-random sequence and said second frequency component of said MDSSS signal is a chipping frequency of said monitor pseudo-random sequence.
 6. An electronic system as recited in claim 1, wherein said third frequency component of said TDSSS signal is a carrier frequency and said third frequency component of said MDSSS is a carrier frequency.
 7. An electronic system as recited in claim 1, wherein said monitor unit comprises a first monitor antenna disposed on said monitor unit and a second monitor antenna disposed on said monitor unit, which said first monitor antenna is cross-polarized relative to said second monitor antenna for measuring said object ranging distance and relative angle from said monitor unit.
 8. An electronic system as recited in claim 1, wherein said second frequency component of said TDSSS signal is a pseudo-random noise sequence input into a first shift register and a second shift register, creating said first phase difference between said second frequency component of said TDSSS signal and said second frequency component of said MDSSS signal.
 9. An electronic system as recited in claim 1, wherein said tracked unit receives a monitor carrier frequency from said monitor unit, wherein said tracked unit includes a phase lock loop that locks said MDSSS signal with said TDSSS signal.
 10. An electronic system as recited in claim 1, wherein said monitor unit further comprises a monitor compass which displays location of said tracked unit within several concentric rings to provide a visual display for a user of said object ranging distance.
 11. An electronic system as recited in claim 1, wherein said monitor unit further comprises a monitor compass which displays said object ranging distance of said tracked unit relative to said monitor unit, and a user selects one zone from several concentric rings of coverage.
 12. An electronic system for locating an object comprising: a monitoring unit; a tracked unit placed on said object receiving a monitor direct sequence spread spectrum (MDSSS) signal from said monitoring unit and transmits a tracked direct sequence spread spectrum (TDSSS) signal to said monitoring unit; a first phase detector placed on said monitor unit to compare a first frequency component of said tracked direct sequence spectrum signal to a monitor first frequency component creating a first phase difference utilized for a coarse accuracy determination of said object distance ranging relative to said monitor unit; a second phase detector included within said monitor unit that compares a second frequency component of said tracked direct sequence spread spectrum signal with a monitor second frequency component to create a second phase difference; and a first detector phase error output determines number of repeated frequency periods of said second frequency component for a medium accuracy determination of range relative to monitor unit of said object range, wherein said first frequency component of said TDSSS signal is a repetition rate of said tracked pseudo-random noise sequence and wherein said second frequency component of said TDSSS signal is chipping frequency of said tracked pseudo-random sequence.
 13. An electronic system as recited in claim 12, further comprising: a third phase detector comparing a third frequency of said TDSSS signal with a third monitor frequency component to create a third phase difference; and an output of second phase detector determines number of repeated frequency cycles of said third frequency component of said TDSSS signal for fine accuracy determination of an object ranging distance between said monitor unit and tracked unit.
 14. An electronic system as recited in claim 12, wherein said third frequency component of said TDSSS signal is a carrier frequency and said third frequency component of said MDSSS signal is a carrier frequency.
 15. An electronic system as recited in claim 12, wherein said monitor unit comprises a first monitor antenna placed on said monitor unit and a second monitor antenna placed on said monitor unit, which said first monitor antenna is cross-polarized relative to said second monitor antenna for measuring said object ranging distance and relative angle from said monitor unit.
 16. An electronic system as recited in claim 12, wherein said second frequency component of said TDSSS signal is a pseudo-random noise sequence input into a first shift register circuit and a second shift register circuit placed with said monitor unit, creating said first phase difference between said second frequency component of said TDSSS signal and a second frequency component of said MDSSS signal, which is a pseudo-random noise sequence.
 17. An electronic system as recited in claim 12, wherein said monitor unit further comprises a monitor compass which displays object ranging distance between said tracked unit and said monitor unit, wherein said a user selects one zone from several concentric rings of coverage for tracking said tracked unit.
 18. A method for detecting the range of an object comprising: placing a tracked unit on said object; transmitting a monitor direct sequence spread spectrum (MDSSS) signal from a monitoring unit; receiving said MDSSS signal at said tracked unit; transmitting from said tracked unit a tracked direct sequence spread spectrum (TDSSS) signal to said monitoring unit; comparing a first frequency component of said TDSSS signal to a first frequency component of said MDSSS signal within a first phase detector; and outputting a first phase shift for coarse accuracy determination of said object range relative to said monitor unit.
 19. The method of claim 18 further comprising the steps of: comparing a second frequency of said TDSSS signal to a second frequency component of said MDSSS signal within a second phase detector; outputting a second phase shift; determining the number of repeated frequency periods of said second frequency of said TDSSS signal. 